The cumulative body of research on borderlands is impressive for its diversity, its interdisciplinarity and its broad scope. One of the richest characteristics of this field is the tendency for scholars to treat borderlands as puzzles which need to be (re)composed. This tendency, however, may impede more ambitious efforts at theorizing borders, as scholars put forward theories based on empirical cases located in a variety of institutional, economic, cultural and environmental contexts. This volume, which includes both theoretical and empirical contributions from leading scholars in diverse fields related to borderlands studies, takes a different approach to theorization and borders. It contends that the theorizing of borders must include the notion of complexity. Instead of proposing a monolithic theory, it adopts strategy that pluralizes theory-building around a core theme which affects different spheres of borderlands studies. Specifically, it examines how power relationships affect border integration in the fields of political cooperation (with a particular focus on local government), spatial planning, environmental management and language policies and practices. While integration processes differ in each of these fields, they are always affected by local power dynamics. Instead of studying the differences that exist between different integration arenas, the contributors to this volume explore the idea of power as a federating theme. The book’s innovative aim is to identify a common thread around which border theory can be constructed, while respecting geographic and thematic differences in border integration processes.